[exim] A query re loopups

I am using Exim from Debian's Sarge, version 4.34-6.
I had a lookup of the form:

${lookup {$local_part@$domain} partial1-lsearch*@ {somefile}}

Lets say the email address way "user@???". Then
I was expecting it to do a sequence of searches like this:

user@???
*@company.com
user@*.company.com
*@*.company.com
user@*.com
*@*.com
*

Instead, it did a series of searches like this:

user@???
*.user@???
*.com
*@company.com
*

Is this the correct behaviour? It didn't seem like a
very useful way to combine the two searches.


Regards,
Russell Stuart